Process of purifying petroleum distillates



Dec. 31, 1929 M. L. CHAPPELL ET AL PROCESS OF PURIFYING PETROLEUMDISTILLATES Filed July 20. 1925 tg wmuxokm \6 S ib INVENTORS. WZa/Wow mge 6 'fying petroleum distillates.

Patented Dec. 31, 1929' UNITED, STATES PATENT fo F1 E. 1

MARVIN L. CHAIPELL,

onmGLEwooD, AND GEORGE J. z rsnn, OF- Los LANGELES,

. CALIFORNIA, ASSIGNORS, BY MESNE ASSIGNMENTS, .TO STANDARD -OIL COMPANYOF CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWAREPROCESS OF PURIFYING PETROLEUM DISTILLATES i Application filed July 20,

This invention relates to a process of puri- Hitherto, the treatment ofpetroleum distillates such as lubricating distillates for the productionof finished products such as lubricating oil has been accomplished bythe well known sulfuric acid treatment followed by a neutralizing withalkali and subsequent clarification with a decolorizing clay. Suchprocess for the treatment of oils is unsatisfactory in -that it involvesthe loss of considerable quantities of valuable hydrocarbons which areremoved by this acid treatment, being combined with sulfuric acid toforma sludge and not recoverable. These losses are exceptionally high wherelarge quantities of strong acid are used, such as in the manufacture ofmedicinal oil, due to oxidation, sulfonation or other chemical actionupon 'the hydrocarbons. This treatment also requires considerablequantities of sulfuric acid, only a part of which can be recovered. Anobject of the present invention is to provide a'process for purifyingpetroleum oils by which this loss of material due to oxidation,sulfonation or chemical action may be avoided; by which the reagent usedfor effecting the purification can be substantially completely recoveredand reused, and by which the cost oftreatment or purification ofpetroleum oils may be decreased.

Another objectof the present invention is to provide a process fortreating petroleum oils by which the oils may be separatedinto productshaving different viscosities by means of a solvent.

The present invention embraces the discovery that, although aniline andpetroleum oil are mutually soluble when heated, upon cooling of asolution of aniline and petroleum oil, separation will take place intoan aniline layer which retains in 'solution certain undepetroleum oilthe body of the desired constituents of the petroleum oil separatingfrom such layers? The constituents retained by an aniline solution atlow temperatures are mainlv as'phaltic compounds, sulfur compounds orunsaturated bodies of high molecular weight. All of these constituentsare undesirable "in high- 1925. Serial No. 44,757.

grade lubricating oils or medicinal oils, but

may be used to advantage in the manufacture of greases or other darkcolored lubricants of high viscosity. 4 Y Thus, the present inventionaffords a physi- .l means for separation of these undesirableconstituents from high-grade lubricating oil while preserving thecharacter of these con stltuents so that they may be utilized in themanufacture of other products, whereas the usual method of treatingpetroleum oils with sulfuric acid removes these constituents ,bychemically uniting. therewith or otherwise chemically changing the sameso that such constituents are renderedpractically valueless or aredifficult to dispose of in the oil refinery.

Various other objects, advantages and diseoveries of the invention willbe apparent from the following description of a preferred example of aprocess embodying the invention. For this purpose reference is made tothe accompanying drawings, which illustrate diagrammatically anapparatus in which or by which the preferred method may be carried out.

In the drawing, 1 indicates a storage tank for aniline oil; 2 indicatesa storage tank for untreated petroleum oil; 3'repre'sents a cone-bottomtank provided with a coil 31 by which the contents of the tank may beheated from 400 F., the process thus being adapted v for thepurification of all lubricating oil distillates andmineral seal oil, thelatter being an oil employed as a. light lubricant or a long-timeburning illuminating oil.

In carrying out the preferred rocess,

tank I 3 is first char ed with a desire quantity'of F petroleum oil romthe storage tank 2 through I 37 and ti've amounts of vvalves 17 and19being open.

' the mixture is then allowed to pipes 12 and 13. Thedesired volume ofaniline is then charged into the tank from the aniline storage tank 1through-pipe 13. The 1 relative amount of" petroleum oil and anilinecharged into the treater may vary Widely, depending upon the characterof petroleum oil to be treated and the degree of purification oftreatment to be thereby effected. For b example, an equal volume ofaniline to that of the oil may be employed.

By means of the centrifugal pump 14, the aniline and oil are thenthoroughlymixed by circulation, the oil being taken from the botpumpedinto the top of the tank 3,

tom and valves 15, 16 and 18 being closed, valves 17, 38 being open.During th s period of operation, the admixture is preferably heated, inorder to effect or to secure a coinplete solution of the petroleum oilin the aniline; such heating may be accomplished by the addition ofsteam through 0011 31 in tank 3. The temperature to Which'the admixtured or solution should be heated varies with the character of distillateused, and the proportions of aniline and petroleum oil used, however, wehave found that with an equ al volume of. aniline, the averagelubricating 011 b about-a temperad distillates are ture of 170 F.solution of the soluble at Subsequent to such complete petroleum oil andaniline While continuing the circulation of the soluion, the solution iscooled down, preferably by the introduction of cold Water through coil31 until separation takes place." The temperature to which the solutionshould be f attained, the

until complete separation of the oil and aniline" layers v has takenplace.

layer, which is of much heavier specific grav ity than the oil, readilysettles to the bottom and is Withdrawn f duced into steam still 4through pipe 21, 20 being condensation the liquids passing thereto arecollected in receiver 6 e aniline has been completely re- After th movedfrom the material charged in the i still 4, theresiduein the still 4,-which conpetroleum oil, the relaaniline as is The aniline fi rom tank 3and introh closed and 18 and b through pipe 26.-

sists of the distillate,

ine 27.

oil extracted from is introduced in the tank 7 through the original Y.

The treated lubricating oil intank 3 after removal 01% the anilinecontaining the ex tracted or purified 011 contains a small percentage ofaniline, which is readily removed y steam distillation in still 5. Forsuch purpose, such treated lubricating oil is introduced into still 5through lines Hand 32, valves 17 and 19 being closed, valve 20 being oilis subjected to. steam introduced into receiver 6 through line 33.

After the aniline has all been removedby such distillation of the oil instill 5, such oil is then transferred to storage tank 8 through pipe 23.l

ensed steam from stills 4 and 5. The aniline and Water may be separatedby the ad-' .dition of being closed, valve 30 being open. coveredaniline is then again introduced into storage tank 1 through pipe 11,through closing of valve 30 an opening of valve 29.

This completes the cycle of operation and then again ready for use inthe aniline is urther treatment.

lVhile theabove description serves to illustratethe method of applyingthe aniline to the oil in a single treatment, We find'that it to the oilin successive treatments in orderto obtain the desired purification.This can readilybe accomplished by merely adding an additional portionof an line to the oil in tank 3 after the separated aniline andextracted oil has been drawn off.

1e operationof circulating, heating, and

cool

nished oil.

Furthermore, this ployed or carried out 1; e purification of the oil,and the oil after such eight pounds per gallon fuming sulfuric acid isrequired, and less fifty percent of the oil is obtained as product afterthis treatment, the re- Receiver 6 contains the aniline and con d agreat saving of oally valueless. By. giving a preliminary drocarbons,sulfur, asphaltic and resinous treatment with aniline, followed byfuming compounds, and separatlng such l qulds. acid, medicinal oil maybe-manufactured at Signed at El Segundo, Cal1f.,th1s th day a greatsaving, both in acid and in oil. of July, 1925.

In the foregoing description, we haye re- I MARVIN L. CHAPPELL, 70

ferred to aniline oil as the purifying reagent;

however, it is understood that it is not in-.

tended to confine the method to the use of aniline oil, since otheraromatic amines, such as the toluidenes, xylidenes, etc., havingSlIIlilar characteristics would also be effective.

Moreover, the process is not confined to the specific treatmentdescribed, as the treatment I may be carried out at a temperature belowwhich the oil and aniline are mutually soluble, and may be carried outat temperatures as low as 15 F. and it is also understood that thisprocess may be applied to an oil whichhas had a preliminary acidtreatment.

It is to be understood that the invention includes all suchmodifications and substitutions as come within the scope of the appendedclaims.

We claim 1. The process of treating viscous high boiling point petroleumdistillates, which comprises mixing aniline oil with the distillate,heating the mixture at a temperature suflicient to produce a homogeneoussolution, and then cooling the mixture to a tem erature where thesaturated constituents o the oil separate from the aniline and the otherconstituents remain dissolved by the aniline.

2. The process of treating viscous high boiling point petroleumdistillates, having an initial boiling point of about 400 E, whichcomprises admixing such oil with aniline oil and heating the admixtureto effect a homogeneous solution, then cooling the solution to effectseparation thereof into liquid oil and aniline oil containingunsaturated constituents of the petroleum oil in solution, and

separating such liquids.

3. A process of treating viscous or lubricating stocks of petroleum oilsfor removal of the unsaturated constituents, which "com prises admixingsuch distillates with approximately an equal volume of aniline oil andheating the admixture to a temperature of at least 170 F. to efi'ect ahomogeneous solution, then cooling the solution to below 80 F.

until the saturated hydrocarbons separate from" the aniline oil and theunsaturated hydrocarbons, and separating such liquids.

4:. A process of treating viscous or lubrieating stocks of petroleumoils for the removal of the unsaturated constituents, sulfur, asphalticand resinous compounds which comprises, admixing such distillates withapproximately. an equal volume of aniline oil and heating the admixtureto a temperature of at least 17 0 F. to eflect a homogeneous solution,then cooling the solution to below F. until the saturated hydrocarbonsseparate from the aniline oil and the unsaturated hy- GEORGE J. ZISER.

